Air preheating means for steam boilers



Aug. 20, 1935. c. w. BROS 2,011,750

AIR PREHEATING MEANS FOR STEAM BOILERS Filed Jan. 22, 1934 INVENTOR z CHESTER W. BROS 23924, M MM Am mean ime Fora STEAM R BOILE S Chester W; Bro's Mixin'eapolis, Minm, assighor to i 1:1 j, 4 l x Wm. BrosBoilr & Manufacturing Company,

' a I i r Minneapolis, a corporation of Minnevsota 7 Applicatiofi January 22, 1931'; Serial No.- 707,175

M I V @Glaims. f(Cl ..122- =-33 6) invention relates' tea fiew and novel as:

paratussupplyinghot air'to the-stoke'r of a boiler to-facilitate combustion and decrease fiue 'gas'tem per'atures so as to increase theov'erall efliciency An object of the invention is to provide incom bination with a*wate1{ tube boiler comprising a furnace and a fuel feeding 'means; an air preheater I ificllldin'ga plurality Of all Circulating tubes dis I it throughsaid tubes-and preheatedtothereby-raiere 'itate'c'ombustion';

a A further and more siiecifi objectof the-invert:

tien istoqfnfovidein combination with a'water tube boiler comprising front andre'ar steam drums, and

' means provided with an air" intake, airpre' cemprising' a bank ofair circulating tubes disso'sedtetween t e furnace and'the'siiiok'e outlet thei eofgwher'eby they are exposed to'the products of edinbustien pas iiigffrsm theifuriiac'e' 5s the smoke outlet; said tubes being open to the atmos= phreat ene end, arid'h avir'ig a' conduit connecting theii'foppo'si-te; ends with theair-intake of the fuel f'eedirig' iiie'ans wherebyl the-air deliveredinto the fufiiace wilrbe rawn througfisaid air circulating tub s eat-preheated. Y furher object is to provise aiepreiieater' adapted for use is cement-ion withboilers of the general character disclosedi'nmyper dingappm eat-1o serial No. 682817; filed Julyzs; 1933'; without 'h avingtoaiterwrchange the; cofistructibu thereof, and which comprises a cameras-cum:

- Iati g tubes-"sodisposed tliatthey viii-1* absorb the iieat n om the products ofcombustioi'f which otherwise would bedischargedthroughthe'smoke' eutlet asfwaste afid'wheieby said preheater may beeperated without additional expense or' equip f Qther objectsof the invention vililbappe'ar'fiom thief-following description; and accompanying dra iiig 'arid war he out iii-the annexed 7 claim the accompanying drawing ,-ther'e Between as used astructiire designed to carry out the varibusobj'e ts of;the invent on; b11611; is to be uhqe stoae that the invention ism-e1: confiuedfto the exact features shown as vari ous changes may bein'iadethe scope of the name which a 55 renows- Inthe drawing: r j

Figure 1' isa sectional elevation of a bOiIershoiiv'" in'g theinvention applied thereto; and

Figure 2 is a detail sectional plan View on the line 2-'-2 of Figure 1, showing the preferred are rangement of the preheater inthe upper portion ofthe boiler. V V V In the selected embodiment of the inventionf here shown, there is'illustrated rorpurpose of disclosure, a boiler similar tothone disclosed in my above mentioned pending application. The boiler comprises front and rear steam 2' and 3, and a; mud drum 4, shown disposed direetly beneath the rear steam drum 3. .Banks ofvvater circulating tubes 5 connect together'the'rear druirr 5 and the mud drum 3', and a bank of angular tubes" 6 establishes communication betweenthe PATENT OFFICE mud drum and the front steam drum 2.- These latteftu'bes provide water-cooled back and 615 walls for the furnace or combustion chamber; 1. Other banks of tubes 8, 9-, and I iconnect-together the steam drums 2 and 3", as clearly shown in Figure 1. V p p Y )i Sifitable baflles I0, l2, l 3, and are shdwii'i'fiterp'osedbetween the tubes constituting 'the batik Stand; funetionto direct the products 15f; com busti'or'r ma tortuous path, as indicated by the arrows in Figure 1.- I I A suitablevvall H: is shown interposed between the front and rear drums 2 and 3* and cooperates with the'top walll6 of the furnaceasing and-the sidewalls I! thereof to provide a chamber H11 which the upper bank of tubes H are disposed.- The chamber [8 is connected at one are to furnace i as will readily be understood by referehce te Figure I, and its opposite end. is; connected to a smoke outlet l9, shown disposed dif rectiir over the front'druml. Thus; the products; 'of' combustion discharging fromthe furnace pass through the chamber f8 before it reaches the smoke outlet I9; V

The furnace is shown provided with a suitable fuel feeding means; such as a conventional'stoker;

enersuy indicated by the numeral M the side walls I1 ofthe furnace casing.-

ends of said air circulating tubes to the air intake of said fuel feeding means, whereby the I air delivered to the furnace is preheated to facilitate combustion.

5. In a water tube boiler, a casing, front and rear steam drums in the upper portion thereof,

a mud drum in the lower portion of the casing substantially directly below the rear steam drum,

a furnace below and between saidsteam drums, a wall interposed between the steam drums and cooperating with the-upper and side walls of said casing to define a chamber, communicating at one end with the furnace, a front smoke outlet communicating with the opposite end of said chamber, a stoker for automatically feeding fuel to the furnace, said stoker having a fan for V Lber to thereby facilitate combustion.

6. In a water tube boiler, acasing, steam drums in the upper portion thereof, a furnace, a wall interposed between said drums and cooperating with certain walls of the casing to define a chamber which communicates with the furnace, a smoke outlet at one end of the chamber, air circulating tubes in said chamber, open to the atmosphere at one side of the boiler, and exposed to the products of combustion passing through the chamber, fuel feeding means including an air intake, and a conduit connecting said air intake to said tubes whereby preheated air is delivered into the furnace from said tubes, when the fuel feeding means is operated.

7. In a water tube boiler, a casing, steam drums in the upper portion thereof, a furnace, a wall interposed between said drums and cooperating with certain walls of the casing to define a horizontal chamber communicating at one end with the furnace and having a smoke outlet at its opposite end, air circulating tubes in said chamber, open to the atmosphere at one side of the boiler and disposed in the path of the products of combustion passing through the chamber, fuel feeding means including an air intake, and a conduit connecting said air intake to said tubes CHESTER W. BROS. 

